The Union was a technologically-oriented faction somewhat similar to the Brotherhood of Steel, although less friendly towards outsiders. They were also a rather insular organization, desiring to "keep to themselves."[1]

Jake, a weapons merchant in the Hub's Old Town, was once a member of the Union, although his wishes to see the world and be his own boss conflicted with the Union's isolationism, driving him to leave the organization.[1] In retrospect, he regards this as the right decision, since the Union was wiped out by mutants after his departure.[2]

The Union of Atomic Workers does not appear anywhere in the Fallout series, having been destroyed ten years prior to the events of Fallout. Jake's brief summation of his history with them is the only mention of the Union.[2]

↑ 1.01.1Jake (Hub)'s dialogue: "{118}{}{Well, I've been around. Used to be with the Union of Atomic Workers. Sort of like the Brotherhood, but less friendly. They wanted to keep to themselves, and I... well, I wanted to see the world and be my own boss, so I left.}"

↑ 2.02.1Jake (Hub)'s dialogue: "{162}{}{The mutants wiped 'em out about ten years ago, so I guess I made the right decision. I eventually settled down here. The cops don't like my trade and I've been rousted more than once, but I'm a helluva lot more honest than most of the merchants here.}"